Communications between end-points on an Internet Protocol (IP) network can be characterized as traffic flows. A traffic flow is a stream of packets that share specific instantiation of Internet Engineering Task Force (IETF) protocol layers. For example, a Real Time Protocol (RTP) flow may consist of the packets of an RTP/UDP/IP protocol instantiation, all of which share the same source and destination IP addresses and UDP port numbers.
Some network architectures permit a network connection with a single IP address to contain multiple datalink flows. Each datalink flow is referred to herein as a “packet data service instance.” In this case, there is a main packet data service instance that is setup when the network connection is established and an IP address is assigned to the end-point, and one or more packet data service instance that can be established and released at a later time.
Each packet data service instance can have differing datalink operational parameters, and implement different Quality-of-Service (QoS) treatments for the traffic flows, so that each particular packet data service instance is associated with its own specific QoS. A traffic classifier on the data-link endpoints is used to direct specific traffic flows onto specific datalink flows.
Network architectures that are structured this way include cellular packet data networks based on CDMA2000, including EV-DO Revision A, (E)GPRS, and UMTS, among others.
Multiple packet data service instances with different operational parameters are sometimes necessary because of unique requirements associated with each application making use of the packet data service instance. For example, packet latency issues do not adversely affect a web-browsing application, so such an application can accommodate a flow with a lower QoS. A Voice over IP (VoIP) application cannot tolerate a datalink flow with significant packet latency, so such an application requires a higher QoS.
FIG. 1 illustrates an example of three packet data service instances and shows the relationships between a mobile station (MS) IP addresses, the (Point-to-Point Protocol Datalink) PPP session, R-P session (Radio Access Network (RAN) to Packet Data Serving Node), R-P connections, service instances, and Service Reference ID (SR_ID) in the CDMA2000 architecture.
At least some of the Cellular Packet Data Network architectures mentioned above currently have procedures available for the network to initiate a primary packet data service instance. For example, if a mobile station is not attached to the network (i.e., the mobile station does not yet have an IP address), and a server on the network wants to send data to the mobile station, the server cannot send IP data until an IP connection is established and the mobile station obtains an IP address. However, the network itself can establish IP connection with the mobile station via a network-initiated procedure. This is in contrast to the usual mode of operation, where the Mobile Station initiates the IP connection and is thereby assigned an IP address.
Although such procedures exist to establish a network initiated main packet data service instance, these procedures are not implemented in practice because of the administrative and addressing problems that occur in this mode of operation. For example, mobile stations capable of network-initiated operation may require a statically assigned IP address.
Procedures for network initiation of secondary packet data service instances are not defined in the standards for the above-mentioned Cellular Packet Data Network architectures. This is because those standards assume that for secondary packet data service instances, the end node (i.e., the mobile station) is already attached to the network and itself will decide based on application requirement when to initiate required secondary packet data service instances. However, the administrative and addressing problems that occur when creating a network-initiated connection to an unattached station are not an issue when establishing secondary packet data service instances because the mobile station already has an IP address, and active signaling channels are established between the mobile and network.
With the rise of interest IP Multimedia networking, online gaming, and protocols such as the Session Initialization Protocol (SIP), network-initiated secondary packet data service instances (such as for CDMA2000 Service Instances or (E)GPRS PDP contexts) can be very useful, in that they provide a secure, authorized, and billable way to establish packet data service instances media, gaming, or other traffic flows that require special QoS handling on the network.